# SDR USAASB99296

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: December 17, 1999
- Submitted: March 26, 2000
- Operation: Air carrier
- Aircraft: [N337US](https://openairdocs.org/aircraft/N337US), registered now
- Make and model: Boeing 737301
- Aircraft serial: 23235
- Engine: Ge CFM563B1
- System (JASC): [7320 · Fuel Controlling System](https://openairdocs.org/jasc/7320)
- Part: Mec
- Part number: 8063207
- Condition: Faulty
- Location: Nr 1 Engine
- Part time: 22,962 hours
- Stage of operation: CL
- Nature of condition: O
- Precautionary procedure: A
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/USAASB99296

## Discrepancy

CLT - FLT 299 - ON CLIMB-OUT FROM CLT, AT FL210, THE NR 1 ENGINE N1 INDICATOR BEGAN FLUCTUATING IN ALL PARAMETERS OF FLIGHT.  THE N1 WOULD SURGE PLUS OR MINUS 7 PERCENT EVERY 7 TO 10 SECONDS.  FLIGHT RETURNED TO FIELD AT CLT AND LANDED WITHOUT FURTHER INCIDENT.  NO EMERGENCY WAS DECLARED.  MAINTENANCE REMOVED AND REPLACED THE NR 1 ENGINE MAIN ENGINE CONTROL.  PERFORMED ENGINE RUN.  OPERATIONAL CHECK AND LEAK CHECK GOOD.  (M)

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